1. Field of the Invention
The present invention relates to an image forming apparatus developing a latent image on an image bearing member with toner, such as a copier, a printer, a facsimile apparatus, etc., a toner supply device for use in the image forming apparatus, and a toner container for use in the toner supply device.
2. Discussion of the Background
It is well known that a toner container containing toner, such as a toner bottle and a toner cartridge, is set in the main body of an image forming apparatus and the toner is supplied to a development device from the toner container. The toner container of this kind is generally made in a stable shape, so that when the used toner container is recycled for reuse or collected for incineration by a manufacturer, because of its bulk, the logistics costs a great deal.
Further, when recycling the used toner container, cleaning the collected used toner container is not so easy, so that the recycling of the toner container is relatively expensive.
On the other hand, recently, a toner container of a volume compressible type has been proposed. However, such a volume compressible toner container has drawbacks that discharging of toner is not so stable, the freedom in conveying the discharged toner is restricted, the performance and the stability of supplying toner are unsatisfactory, toner scattering is caused in replacement, and the installation location of a toner supply device using the toner container in an image forming apparatus is restricted.
To solve the above-described drawbacks, the applicant of the present invention has proposed to use a suction-type uniaxial eccentric, screw pump, called a Monoe pump, for a toner conveyance device. The pump is constituted of a rotor of a male screw type, which is formed of a material having rigidity, such as metal, in an eccentric screw shape, a stator of a female screw, the inside of which is formed in a two-fold screw shape by an elastic material, such as rubber, and which is fixedly set, and a holder made of resin, which encloses the rotor and the stator and forms a conveying path for powder, such as toner. The male screw type rotor inserted into the female screw type stator is rotated around the eccentric center via a connection rod connected with a drive device within a hole of an elliptic shape in the cross section of the stator (an eccentric rotation space). Thereby, a pumping function (a strong self-priming force and a suction pressure) is generated, and toner is sucked into the stator and is discharged through the stator. The toner is fluidized by supplying compressed air before being sucked and after having been discharged by an air supply device.
Japanese Patent Laid-open publication No. 2001-324863 describes a toner container for use in an image forming apparatus using such a Monoe pump. The toner container includes a container bag in a hermetic state, which is deformable by a suction pressure of the Monoe pump. A self-closing valve made of a seal member is provided to an opening part of the container bag, and a cap member provided with a toner discharge part is attached to a tip end of the container bag.